Facebook Graph API won't return email address

The Marcus' answer leads me to the real problem I was facing.

Debugging with the Facebook Explorer tool I was able to figure out that I should set the email scope at the FB.api() method after a successful login.

FB.login(function(response) {
    if (response.status === 'connected'){
        FB.api('/me?fields=id,email,name', function(data) {
        console.log( data.email ) // it will not be null ;)
    })
}, {scope: 'email'});

It is not quite clear at the Quickstart guide and I hope it helps someone else, too.

I had the same problem and I think I found out why: If the user has an unconfirmed email in Facebook (i.e. Facebook sent him a validation mail to his email address but he didn't respond) Facebook WILL NOT pass that email to your app even if he gave you the email permissions (!!!).

So what I did is use his Facebook email if he has a user name (i.e. [email protected]).

After i got my bug report marked as duplicate, and i read all posts and links there, i got what caused this problem for me and how to fix.

The Problem Facebook seems to sometimes forget what your primary e-mail is on the graph API (But it still there in the preferences.)

Solution The user affected must remove the e-mail, save settings, then re-add the address, re-confirm, then make it primary. This fixed my account both on my sandbox app, and other apps where Facebook login don't used to work.